Electrical contact or circuit component



May l, l956 C D. M. suLLlvAN 2,744,180

ELECTRICAL CONTACT OR CIRCUIT COMPONENT Filed March 30, 1953 ATTO/@NE YS' United States Patent C 2,744,180 ELECTRICAL CONTACT OR CIRCUIT COMPONENT Daniel M. Sullivan, Bridgeport, Conn. Application March 30, 1953, Serial No. 345,310 19 Claims. (Cl. 20G-466) This invention relates to electric circuit components, and more particularly to circuit panels or switch bases having conducting or contact elements separated by electrical insulation` There have been provided in the past, especially in connection with electrically-operated business machines, computers, etc., control circuit components in the form of panels or blocks comprising metallic contact elements carried on an insulating base member, such components or assemblies constituting in some instances part of a switch means for the purpose of controlling various operations in the machine. It is desired that such panels withstand a long period of use, involving many makeand-break cycles wherein switch blades ride over both the contact elements and the interposed insulating surfaces. Heretofore, switch contact or circuit panels have been made up of metallic elements which were either imbedded in insulating plastic base members or imprinted thereon, with insulating plastic material occupying the spaces between the contact elements. A drawback of this prior type of construction is that it cannot withstand suhcient usage, breaking down after a moderate number of4 cycles of operation and requiring replacement. Such replacement is often costly since it involves down time of the machine, and also the employment of skilled personnel.

An object of the present invention is to provide an improved contact or circuit component in the form of either a panel or a block and an improved method of making the same, said component comprising a plurality of metallic elements arranged in various configurations, and comprising insulating material disposed between the elements, characterized by relatively great resistance to wear and abrasion and an extremely long life, or ability to withstand a very large number of make-and-break cycles.

Another object of the invention is to provide an improved contact or circuit component as above set forth, which is electrically eflcient, providing low contact and electrical resistance.

A further object of the invention is to provide an improved contact or circuit panel as above set forth, which is economical to fabricate and rugged and reliable in its operation.

In accomplishing the above objects I provide a novel circuit or contact component comprising a body or base member formed with a glass, glass-like or glazed surface and having imbedded in it metallic Contact elements, the organization being characterized by a strong and preferably fused bond between the metallic elements and the said surface, and by a smooth and polished path or face for engagement with sliding contacts or their equivalent.

In accordance with the method of the invention l lirst provide recesses in the body or base, as by molding the body with said recesses, or by grinding, etching or the like. l then apply to said recesses a metallic composition, preferably in the form -of paint, having a fluxing agent or substance. Thereafter the body and the metallic paint are brought up to a iiring temperature which renders the glass or glazed surface semi-plastic and causes it to bond with the ux material. The metallic paint is thus securely bonded to the surface, and this operation may 2,744,180 Patented May 1, 1956 be repeated a number of times whereupon, after the lnal cooling, the resultant surface of the panel may be ground and polished to render it perfectly smooth. The metallic inserts as well as the glass or glazed surface disposed between the inserts are resistant to a marked degree to abrasion, and enables the body or panel to be used for an extended period of time, representing a very large number of cycles of operation, without failure. On preliminary test a circuit component made in accordance with my invention has been put through eight million cycles of operation without showing any appreciable wear, and on the basis of this performance my improved circuit components may be expected to withstand many million cycles of operation. I may repeat the application of the metallic paint as much as ve or more times, going through the tiring process after each application, where it is desired to build up the thickness of the metallic elements of the body or panel.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure l is a fragmentary transverse sectional view of one specific embodiment of the invention, showing a circuit panel illustrating the method or process of the invention, the panel body being recessed and having applied to it in the recess thereof a layer of metallic paint.

Fig. 2 is a view like Fig. 1, but showing a number of layers of metallic paint applied in the recess.

Fig. 3 is a view of the panel of Fig. 2 after its surface has been ground and polished; a sliding contact is also shown positioned on the metallic element.

Fig. 4 is a view like Fig. 3, but illustrating a modification of the invention wherein a single thick layer of metallic paint has been applied to the recess of the panel, and the panel then ground and polished.

Fig. 5 is a top or plan view of a circuit of contact panel made in accordance with the invention.

Fig. 6 illustrates a use of the contact panel, being a fragmentary sectional view on line 6 6 of Fig. 5, showing a pair of switch contacts engaging two metallic elements of the panel.

Fig. 7 is a fragmentary transverse sectional View of av circuit panel illustrating a different form of the invention,.

wherein the panel body is formed of a glazed ceramic such as porcelain or the like.

Fig. 8 is a view like Fig. 7, but illustrating a modification of the invention when employing glazed ceramic bodies or panels.

Fig. 9 is a view like Figs. 7 and 8, but illustrating another modification of the invention when using glazed ceramic bodies.

Referring to Fig. 5 the completed contact or circuit component shown comprises a plurality of metallic elements 10 which are imbedded in a base formed of a glass body or panel 11. While the base 11 and the contact elements 10 have been shown as rectangular, it should be understood that these may have other shapes or congurations as required by the particular application or use to which they are put.

ln accordance with the method of lthe invention, to prepare the panel ll for the reception of the metallic elements 10 I provide recesses 12 in the face of the panel, said recesses having the same shape or outline as the elements. The recesses may be formed by a grinding operation for example, but I preferably form them by etching the face of the panel with a suitable acid.

It will be understood that prior to the application of the acid to the panel, the surface of the panel may be coated with a material which is impervious to or not affected by the acid, and portions of such coating may then be removed to expose the surface of the glass to the action of the acid. This may involve a photographic process as is well known in the art, or any other method found suitableto produce the required configurations. lf acid is used, I have found that the etching may be allowed to proceed until a recess-,having a depth of approximately .005 is produced.. The bottomv of such recessI will be rough or uneven, as clearly shown inFigs. l` through 4, and this will strengthen the bond. between the metallic element it() and. the panel, since the. roughness will provide a more effectiveholding surface. The panel 11 is thoroughly washed tov remove all traces of the etching acid, and then dried to remove the moisture. Thereafter l apply a coat of flux-containing metallic pa'mt i3 to the recesses, as shown in Fig. l. i have found that a paint suitable ,for this purpose includes silver particles, a lacquer vehicle comprising organic solvents, and a flux material. The latter may be lead borosilicate, either with or with out bismuth oxide. After the application of the layer of paint to the recesses of the panel 11 the latter is placed inan oven and subjected to a tiring temperature inthe neighborhood of 1000 F. The silver in the paint normally will not melt but will remain as discrete contacting particles bonded together by the ux; the lacquer vehicle will be boiled off and the flux material will bond with the glass which has become semi-plastic at this temperature. After tiring, the panel is removed from the oven and allowed to cool whereupon additional layers of paint are applied in the recesses as indicated in Fig. 2. After the application of each layer of paint, the firing procedure is repeated. When the final layer of paint has been fired and the panel cooled, the excess paint is removed, as by grinding, and the surface is polished to make it perfectly smooth. The nished surface is indicated in Fig. 3. Alternatively, the entire Contact side of the panel may be ground and polished, this being desirable Where distortion of the glass has occurred or if an especially smooth face is wanted.

As an alternative procedure the metallic paint may be applied in a single thick layer as indicated in Fig..4 and the resultant article fired, cooled, ground and polished. Or the paint may be applied in two layers or three, or morev as desired.

I have found that a circuit or contact panel formed in accordance with the method of this invention is extremely resistant to abrasion due to the excellent wearing qualities of the glass insulation disposed between the metallic elements 10, and due to the wear-resistant properties of the metal, whether it be silver or other metal, of which the contact elements are composed. The fusion of the flux material and bonding of the latter to the semi-plastic glass during the tiring of the panel results in a structure which is virtually one piece for all practical purposes, even though the particles of silver remain discrete, since they are held in contact with each other andv bonded together and to the glass by the uxing substance. The flux permeates the body of each metallic element and securely bonds the element to the glass base 11. Where the shrinkage characteristic of the metallic paint is matched to that of the glass panel 11, virtually no cracks or crevices will exist at the marginal portions of the nserts where they meet the glass. lf the shrinkage coefcients are not matched, minute cracks may exist at these locations; however this will not result in the panel being imperfect or undesirable for the use desired, since the useful life and number of cycles of operation will in any event be greatly in excess of circuit components heretofore devised wherein plastic insulation is utilized.

A circuit component made in accordance with this invention has been found to withstand an extremely large number of makeand-break cycles, suiting it admirably for use in electrically controlled business machines, computers, electronic equipment and the like.

The operations required to produce such circuit components are few and simple, involving inexpensive mate rials and equipment, thereby making for a low fabrication "cost. Due to the extremely long life, maintenance cost is practically nil, so that a low cost per cycle of operation may be expected.

Since the insulating qualities of glass and the conducting qualities of silver are excellent, the improved circuit components of this invention have high electrical efficiency.

Instead of employing glass bases, or panels, material such as ceramic having glazed' surfaces may be used, in accordance with the invention, and the terms glass surface and glazed surface as used herein are intended to cover all surfaces having the nature of glass, produced by a firing process and involving basic materials such as sand, glazing composition, silicates, etc.

Referring to Fig. 7 a clay or ceramic body 14V is shown having a glazed surface 15 which has been etched by acid to provide a recess therein, said recess having been filled by metallic paint 16 containing flux which is bonded to the glazed surface 15 of the body 14. The resultant surface has been ground and polished to make it perfectly smooth.

In Fig. 8 a ceramic panel 17 is shown, having a preformed or molded recess 18, the entire surface of the panel 17 being glazed. The recess in the glazed surface has been lled with metallic paint 19 containing flux which is bonded to the glazing by the tiring process. The resultant surface of the panel has been ground and polished to present a smooth face.

In Fig. 9 a ceramic panel 2i) is molded or formed with a recess 21 and provided with al glazed surface 22. The glazing may be either withheld from the recess 21, or removed from the recess by etching or other suitable procedute. A metal insert 23 containing a flux which is bonded to the glazed surface 22 and to the ceramic body 20, is shown in the recess 21.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

l claim:

l. As a new article of manufacture, an electrical circuit component comprising a glass body having an exposed surface and having imbedded in said surface a metal conducting member containing throughout its structure a linx bonded to said body.

2. As a new article of manufacture, an electrical circuit component comprising a glass body having a smooth exposed surface and having imbedded in said surface a metal contact member containing throughout its structure a flux bonded to said body, said contact member having a smooth exposed surface liush with the exposed surface of the glass body.

3. As a new article of manufacture, an electrical circuit component comprising a glass body having a recessed portion bounded by a smooth exposed surface and having in and bonded to said recessed portion a metallic conducting member comprising a multiplicity of ydiscrete metallic particles and flux bonded together, said member having a smooth exposed surface llush with the exposed surface of the glass body.

4. As a new article of manufacture, an electrical circuit component comprising a glass body having a rough recessed portion bounded by a smooth exposed surface and having in and bonded to said recessed portion a metallic conducting member comprising a multiplicity of discrete metallic particles and flux bonded together, said member conforming to the rough surface of the recessed portion and having a smooth exposed surface flush with the exposed surface of the glass body.

5. As a new article of manufacture, an electrical circuit component comprising a glass body having a rough recessed portion bounded `by a smooth exposed surface and having in said recessed portion a metallic conducting member containing Vthroughout its structure a ux bonded to said body, said member conforming Ato the rough surface of the vrecessed portion landhaving a smooth exposed surface llush with the exposed surface of the glass body.

6. As a new article of manufacture, an electrical circuit component comprising a glass body having a rough recessed portion bounded by a smooth exposed surface and having in said recessed portion a metallic conducting member containing throughout its structure discrete par4 ticles of metal and a ux bonded to said body and bonding together the particles of metal, said member conforming to the rough surface of the recessed portion and having a smooth exposed surface flush with the exposed surface of the glass body.

7. As a new article of manufacture, an electrical circuit component comprising a glass body having a recessed portion bounded by a smooth exposed surface and having in said recessed portion a metallic conducting member containing throughout its structure discrete particles of metal and a flux bonded to said body and bonding together the particles of metal, said member having a smooth exposed surface ush with the exposed surface of the glass body.

8. As a new article of manufacture, an electrical circuit component comprising a glass body having a recessed portion bounded by a smooth exposed surface and having in said recessed portion a metallic conducting member containing throughout its structure discrete particles of silver and a flux bonded to said body and bonding together the particles of silver, said member having a smooth exposed surface ush with the exposed surface of the glass body.

9. The method of producing an electrical circuit component which includes the steps of forming a recess in a face of a glass body, placing a substance containing throughout its structure metallic particles and flux in said recess, subjecting the body and lled recess thereof to a ring temperature to fuse the tiux of said substance with the glass body, and removing material from the face of the body and from the filled recess to cause the metallic particles and fused ux in the recess and the surrounding surfaces of the body to be smooth and flush with each other.

l0. The method of producing an electrical circuit component which includes the steps of forming a recess in a face of a glass body, placing a substance containing throughout its structure metallic particles and flux in said recess, subjecting the body and filled recess thereof to a firing temperature to fuse the flux of said substance with the glass body, and smoothing out the resultant face of the body to cause the metallic particles and fused ilux in the recess and the surrounding surfaces of the body to be smooth and flush.

11. The method of producing an electrical circuit component which includes the steps of forming a recess in a face of a glass body, placing a substance containing throughout its structure metallic particles and 'ux in said recess to overtill the recess, subjecting the body and over# lled recess thereof to a firing temperature to fuse the llux of said substance with the glass body, and removing material from the substance in the recess to cause the metallic particles and fused flux in the recess to be smooth and ush with the surrounding surfaces of the body.

12. The method of producing an electrical circuit component which includes the steps of forming a recess in a face of a glass body, placing a substance containing throughout its structure metallic particles and flux in said recess, subjecting the body and filled recess thereof to a firing temperature to fuse the flux of said substance with the glass body, repeating the application of metallic substance and tiring to build up the metal in the recess, and smoothing olf the resultant face of the body to cause the metallic particles and fused flux in the recess and the surrounding surfaces of the body to be smooth and flush.

13. The method of producing an electrical circuit component which includes the steps of forming a recess in a face of a glass body, placing a substance containing throughout its structure metallic particles and llux in said recess, subjecting the body and filled recess thereof to a firing temperature to fuse the flux of said substance with the glass body, repeating the application of vmetallic substance and ring to build up the metal in the recess until it extends above the surrounding surface of the glass body, and smoothing off the resultant face of the body to cause the metallic particles and fused flux in the recess and the surrounding surfaces of the body to be smooth and ilush.

14. The method of producing an electrical circui-t component which includes the steps of etching a face of a glass body to form a recess therein, placing a substance containing throughout its structure metallic particles and ilux in said recess, subjecting the lbody and filled recess thereof to a firing temperature to fuse the flux of said substance with the glass body, repeating the application ofmetallic substance and firing to build up lthe metal in the recess until it extends above .the surrounding surface of the glass body, and smoothing od the resultant face of the body to ecause the metallic particles and fused flux -in the recess and the surrounding surfaces of the body to be smooth and flush.

15. As a new article of manufacture, an electrical circuit component compris-ing .a ceramic body having an exposed glazed surface and having -imbedded in said surface a metal conducting member containing throughout its structure a ilux bonded to the glazed surface of said body.

16. As a new article of manufacture, an electrical circuit component compr-ising a body having an exposed glazed surface and having imbedded in said surface a metal conducting member containing throughout its structure a flux bonded to the glazed surface of said body.

17. The method of producing an electrical circuit component which includes lthe steps of forming a recess in a face of a glazed body, placing a substance containing throughout its structure metallic particles and ilux in said recess, subjecting the body and filled recess thereof to a firing temperature to fuse the ux of said substance with the glazed surface of the body, and removing material from the glazed surface of the body and from the filled recess to cause the metallic particles :and fused ilux in the recess and the -surrounding surfaces of the body to be smooth and flush with each other.

18. The method of producing an electrical circuit component which includes the steps of etching a face of a glazed body to form 4a recess therein, placing a substance containing throughout lits structure metallic particles and llux in said recess, subjecting the body and Vfilled recess thereof to a tiring temperature to fuse the flux of said substance with the .glazed surface of the body, repeating the application of metallic substance and firing to build up the metal in ythe recess until it extends above the surrounding glazed surface of the body, and smoothing off the resultant face of the body to cause thel metallic particles and fused flux -in the recess and the surrounding surfaces of the body to be smooth and flush.

19. The method of producing an electrical circuit component which includes the steps of filling a recess in a body having a glazed surface with a substance containing throughout its structure metallic particles and flux, subjecting the body and filledrecess -thereof to a firing temperature to fuse the flux of said substance with the glazed surf-ace of the body, and removing material fnom the exposed glazed surface of the body and from the lling of ythe recess to cause the metallic particles and fused nur in the recess and the surrounding surfaces of the body to be smooth and flush with each other.

References Cited in the le of this patent UNITED STATES PATENTS 604,688 Moore May 24, 1898 611,206 Moore Sept. 20, 1898 751,028 Thomson Feb. 2, 1904 2,385,580 Knox Sept. 25, 1945 2,694,126 Binstock Nov. 9, 1954 

1. AS A NEW ARTICLE OF MANUFACTURE, AN ELECTRICAL CIRCUIT COMPONENT COMPRISING A GLASS BODY HAVING AN EXPOSED SURFACE AND HAVING IMBEDDED IN SAID SURFACE A METAL CONDUCTING MEMBER CONTAINING THROUGHOUT ITS STRUCTURE A FLUX BONDED TO SAID BODY. 